Currently, the predominant pull buoys for swimming involve a figure-eight shaped float that a swimmer holds tight between his/her thighs. Other pull buoys involve an ankle cuff with openings on the outside of each ankle cylinder which allows the swimmer to insert or remove his/her ankles from the buoy. One ankle cuff approach involves fins on the buoy while another approach excludes the fins.
The existing solutions require varying degrees of inconveniences while swimming. For example, the figure-eight shaped float requires the swimmer to squeeze his/her thighs tightly to keep the pull buoy in place. The pull buoy requires frequent placement adjustments while swimming and is difficult to keep in place, for example, when kicking off a wall of a pool to change direction. The ankle buoy approach is easier than the figure eight format because the buoy stays in place by hanging around the ankles. However, this design also has key limitations. First, because both ankles are cuffed, the ankle buoy creates some difficulty when the swimmer turns around and kicks off a wall. Second, the ankle buoy may not maintain a precise position due to ample room present within the holes, leaving the ankles ample freedom, so the ankle buoy does not provide a snug fit. If the swimmer pulls the ankle buoy upwards to the calf or below the knee, then there is pressure around the circumference of the calf but there is not sufficient pressure to keep the ankle buoy in place during swimming. Finally, the presence of the flotation device so far to the tail end of the body creates an unnatural ballast, increasing the difficulty for the swimmer to keep the legs aerodynamically streamlined behind the body, and the legs wag.
Another approach involves an upside down T-shaped flotation device that is held between the legs with a strap that is wrapped around the swimmer's waist. This approach improves upon the figure eight design but the T-shape device is not able to immobilize the swimmer's legs and allows the legs to sink. As a result, the T-shaped pull buoy does not streamline the swimmer's legs, which is often the goal of a pull buoy.
Another approach includes a simple rubber band that binds the ankles together without any flotation. Again, this device allows the swimmer's legs to sink.